Previous reconnoissances made, first by Brigadier-General W. F. Smith, Chief-Engineer, and afterward by Thomas, Sherman, and myself, in company with him, of the country opposite Chattanooga and north of the Tennessee River, extending as far east as the mouth of the South-Chickamauga and the north end of Missionary Ridge, so far as the same could be made from the north bank of the river without exciting suspicions on the part of the enemy, showed good roads from Brown's Ferry up the river and back of the first range of hills opposite Chattanooga, and out of view of the enemy's positions. Troops crossing the bridge at Brown's Ferry could be seen, and their numbers estimated by the enemy; but not seeing any thing further of them as they passed up in rear of these hills, he would necessarily be at a loss to know whether they were moving to Knoxville, or held on the north side of the river for further operations at Chattanooga. It also showed that the north end of Missionary Ridge was imperfectly guarded, and that the banks of the river from the mouth of South-Chickamauga Creek, eastward to his main line in front of Chattanooga, was watched only by a small cavalry picket. This determined the plan of operations indicated in my despatch of the fourteenth to Burnside. Upon further consideration — the great object being to mass all the forces possible against one given point, namely, Missionary Ridge, converging toward the north end of it — it was deemed best to change the original plan, so far as it contemplated Hooker's attack on Lookout Mountain, which would give us Howard's corps of his command to aid in this purpose; and on the eighteenth the following instructions were given Thomas: not be allowed to escape with an army capable of doing any thing this winter. I can hardly conceive the necessity of retreating from East-Tennessee. If I did at all, it would be after losing most of the army, and then necessity would suggest the route. I will not attempt to lay out a line of retreat. Kingston, looking at the map, I thought of more importance than any one point in East-Tennessee. But my attention being called more closely to it, I can see that it might be passed by, and Knoxville and the rich valley about it possessed, ignoring that place entirely. I should not think it advisable to concentrate a force near Little Tennessee to resist the crossing, if it would be in danger of capture; but I would harass and embarrass progress in every way possible, reflecting on the fact that the army of the Ohio is not the only army to resist the onward progress of the enemy.
A copy of these instructions was furnished Sherman with the following communication:All preparations should be made for attacking the enemy's position on Missionary Ridge by Saturday at daylight. Not being provided with a map giving names of roads, spurs of the mountain, and other places, such definite instructions cannot be given as might be desirable. However, the general plan, you understand, is for Sherman, with the force brought with him, strengthened by a division from your command, to effect a crossing of the Tennessee River, just below the mouth of the Chickamauga, his crossing to be protected by artillery from the heights of the north bank of the river, (to be located by your Chief of Artillery,) and to secure the heights from the northern extremity to about the railroad tunnel before the enemy can concentrate against him. You will cooperate with Sherman. The troops in Chattanooga valley should all be concentrated on your left flank, leaving only the necessary force to defend fortifications on the right and centre, and a movable column of one division in readiness to move whenever ordered. This division should show itself as threateningly as possible on the most practicable line for making an attack up the valley. Your effort, then, will be to form a junction with Sherman, making your advance well toward the northern end of Missionary Ridge, and moving as near simultaneously with him as possible. The junction once formed, and the ridge carried, connections will be at once established between the two armies by roads on the south bank of the river. Further movements will then depend on those of the enemy. Lookout valley, I think, will be easily held by Geary's division, and what troops you may still have there belonging to the old army of the Cumberland. Howard's corps can then be held in readiness to act either with you at Chattanooga or with Sherman. It should be marched on Friday night to a position on the north side of the river, not lower down than the first pontoon-bridge, and then held in readiness for such orders as may become necessary. All these troops will be provided with two days cooked rations, in haversacks, and one hundred rounds of ammunition, on the person of each infantry soldier. Special care should be taken by all officers to see that ammunition is not wasted or unnecessarily fired away. You will call on the engineer department for such preparations as you may deem necessary for carrying your infantry and artillery over the creek.
Inclosed herewith I send you copy of instructions to Major-General Thomas, for, having been over the ground in person, and having heard the whole matter discussed, further instructions will not be necessary for you. It is particularly desirable that a force should be got through to the railroad between Cleveland and Dalton, and Longstreet thus cut off from communication with the South; but being confronted by a large force here, strongly located, it is not easy to tell how this is to be effected until the result of our first effort is known. I will add, however, what is not shown in my instructions to Thomas, that a brigade of cavalry has been ordered here, which,